Muscle
Iliacus
Broad iliac-fossa partner of psoas major
High-yield
Femoral nerve branches supply iliacus. Most fibers join the iliopsoas tendon, but some attach directly near the lesser trochanter, so the distal muscle-tendon arrangement is not identical in everyone.
Overview
Iliacus fills much of the inner surface of the ilium. Its fibers converge toward psoas major and travel with it across the front of the hip, forming the iliopsoas group that helps lift the thigh.
Reference facts
- Origin
- Upper iliac fossa, inner iliac crest and adjacent sacral and pelvic ligament attachments
- Insertion
- Mainly through the iliopsoas tendon to the lesser trochanter; some fibers attach to neighboring proximal femur
- Action
- Flexes the hip and contributes to hip stability; with the femur fixed, helps draw the pelvis and trunk forward
- Innervation
- Muscular branches of the femoral nerve, with L2-L3 commonly emphasized
- Blood supply
- Chiefly iliolumbar branches, with contributions from deep circumflex iliac, obturator and femoral arterial networks
Clinical correlation
A hematoma within or around iliacus can press on the nearby femoral nerve. This can combine groin pain with weakness and altered sensation; nerve symptoms may develop after the bleeding rather than immediately.
Frequently asked questions
What does the iliacus do?
Flexes the hip and contributes to hip stability; with the femur fixed, helps draw the pelvis and trunk forward.
What nerve innervates the iliacus?
The iliacus is innervated by the muscular branches of the femoral nerve, with L2-L3 commonly emphasized.
Where does the iliacus attach?
Origin: Upper iliac fossa, inner iliac crest and adjacent sacral and pelvic ligament attachments. Insertion: Mainly through the iliopsoas tendon to the lesser trochanter; some fibers attach to neighboring proximal femur.
What is the blood supply of the iliacus?
Chiefly iliolumbar branches, with contributions from deep circumflex iliac, obturator and femoral arterial networks.